THE SKIN AND ITS APPENDAGES. 



1137 



In structure the epidermis consists of several layers of epithelial cells agglutinated 

 together and having a laminated arrangement. These several layers may be 

 described as composed of four different strata from within outward : (1) The stratum 

 Malpighii, composed of several layers of epithelial cells, of which the deepest layer 

 is columnar in shape and placed perpendicularly on the surface of the corium, 



Stratum corneum. { 



Stratum lucianm 

 Stratum granulosum 



Stratum Malpighii.< 



Stratum germinativumA 



-Nerve-fibrils. 



FIG. 678.- Section of epidermis. (Ranvier.) 



their lower ends being denticulate, to fit into corresponding denticulations of the 

 true skin; this deepest layer is sometimes termed the basilar layer or stratum 

 germinativum : the succeeding laminae consist of cells of a more rounded or polyhe- 

 dral form, the contents of which are soft, opaque, granular, and soluble in acetic acid. 



FIG. 679.-Microscopic section of skin, showing the epidermis and derma ; a hair in its follicle ; the erector 

 pili muscle; sebaceous and sudoriferous glands. 



They are often marked on their surfaces with ridges and furrows, and are covered 

 with numerous fibrils, which connect the surfaces of the cells : these are known as 

 prickle cells. (See page 1075.) They contain numerous epidermic fibrils which 

 are stained violet with hsematoxylin and red by carmine, and form threads c 



72 



